DESCRIPTION (Adapted from applicant's description): The objective of this proposal is to train pediatric M.D. and M.D./Ph.D. physician-scientists for successful careers as independent investigators in the field of developmental physiology and cell biology, specifically as it relates to understanding the ontogeny and regulation of membrane transport. Three priorities for research training have been identified: 1) To identify and characterize transport proteins and their functional interactions as they relate to cell growth, differentiation and the maintenance of homeostasis; 2) To determine the developmental and genetic bases for inherited and acquired disorders of membrane transport; and 3) To develop new therapeutic strategies (e.g., gene therapy) for disorders of membrane transport. The inclusion of both clinical and basic science faculty preceptors with research interests and expertise in these related fields will provide a basic research training experience. All candidates for this training program will be expected to devote a minimum of three years to research training.